Variously configurable rotating biological contactor and prefabricated components therefor

ABSTRACT

Improved fabricated subcomponents, components and rotating biological contactor embodiments that are assembled from, and that incorporate, such subcomponents and components are achieved. The components comprise tank sections, bulkheads, contactor drums, paddle wheels, shaft assemblies including associated bearings and supports, each of which may be assembled from preformed subcomponents if desired. Rotating biological contactors are assemblable at an installation site, which may be a confined space if desired, by two men with simple tools. In an assembled rotating biological contactor, the shaft assemblies can rotated by an electric motor, by fluidic pressure exerted upon paddle wheel blades, or by both in combination.

FIELD OF THE INVENTION

This invention lies in the field of rotating biological contactors whichare comprised of prefabricated subassemblies that can be variouslyassembled to achieve various configurations and various operatingfunctions.

BACKGROUND OF THE INVENTION

Rotating biological contactors (RBC's) are used for the biologicaltreatment of wastewater. Such a device or system characteristicallyutilizes at least one wastewater contacting medium which is fixed upon arotatable shaft that is arranged to continuously revolve in a reservoirof wastewater to be treated. As the contacting medium revolves, abiological culture naturally develops on it and this culture has thecapacity for digestion of contaminating substances in the wastewater. Asthe contacting medium bearing the culture rotates, it experiencesalternatively exposure to wastewater and then to oxygen (air), therebyachieving aerobic treatment of the water contaminants. Alternatively,the medium can be completely submerged within the wastewater for anoxicand/or anaerobic processes to treat the waste stream.

Currently, what is believed to be the most common commercially availableform for an RBC utilizes a single, horizontally rotating shaft abouteight meters (about 25 feet) long which carries contacting media orcontactors having a gross diameter of about four meters (about 12 feet)which provide a total of about 10,000 square meters (about 100,000square feet) of media surface area. Commonly, such one shaft extendsacross a single reservoir or stage. Multiple reservoirs (or multiplestages) can be used which are preferably arranged so as to besuccessively coaxial or longitudinally adjacent to achieve a maximizedwastewater treatment. In RBCs having a longitudinal axis, the tank ortrough (usually hemi-cylindrically sided) may be subdivided into aplurality of axially aligned,

longitudinally adjacent stages by means of transversely extendingbaffles or bulkheads. Such a multistaged-type of RBC is commerciallyavailable in various sizes from various manufacturers. In a commerciallyavailable RBC, circular contactors may be employed which have contactordiameters ranging from about 0.7 meters (about 2 feet) to about 4 meters(about 12 feet), and the number of individual stages ranges upwards fromone.

It is most often desirable to design an RBC with multiple stages,generally three or more. Experience teaches that by providing therequisite amount of media (contactor) surface area for bacterialcolonization into multiple, sequential stages, performance is enhanced.This sequencing of stages promotes a tendency for bacterialspecialization to occur along the sequence as specific contaminants aredestroyed by those bacterial species which have the fastest rate ofconsumption. This is comparable, for example, to making an activatedsludge reactor very long or a packing tower (trickling filter) verytall. If the same media surface area were divided among stages inparallel, even though the total flow rate through and the total volumeof the sum of all stages (and hence the waste water contact time perunit area of media surface area) remain then same, the advantage ofsequential processing (and bacterial specialization) would be missed.

Commonly, the trough or tankage portion of a conventional largecommercially available RBC is typically locally designed and built toaccommodate rotating circular contactor(s) that are supported on anassociated shaft and shaft drive assembly purchased from themanufacturer. Such a tankage portion is commonly fabricated on-site ofpoured concrete. Smaller, test RBC units are available that employ steeltankage. Also, still smaller units suitable for residual wastewatertreatment, and for the aquaculture and aquarium industries, areavailable which have tankage portions comprised of fiberglass or otherplastic. However, in all known commercial forms of RBC's, the tankageportions are individually designed and fabricated either to order or aspackaged assemblies, and all such RBC embodiments are either fixed, orare characterized by having very limited variability in operationalconfiguration. Their stationary components, such as the tankage portion,are dimensionally fixed.

For an RBC installation to treat wastewater, it is desirable initiallyto evaluate and characterize the particular wastewater and to design andadapt a RBC system for usage with that particular wastewater so thatsystem parameters are optimized for best or maximized effectivetreatment of that wastewater. Various RBC design procedures and criteriaare known to those skilled in the art. If desired, for design purposes,a miniaturized RBC embodiment may be preliminarily used to evaluatesamples of the wastewater and identify operating parameters. Forexample, one suitable miniaturized RBC system is disclosed in my U.S.Pat. No. 4,737,278.

It has become routine for a wastewater to be characterized and formathematical models to be used to design RBC installations for treatingthat wastewater; see, for example, “Design of Biological TreatmentSystems,” pages 25-66-25-76 in Perry's Chemical Engineers' Handbook,Seventh Edition (1997) McGraw Hill. However, there are wide variationsin wastewater characteristics.

Because of the many variations in application situations, a need existsfor RBC apparatus which can be rapidly, simply, reliably andeconomically fabricated and assembled, and then later, if need be,modified and/or expanded even after an initial installation has beencompleted and operated. A plurality of various potential RBC apparatusconfigurations would be desirable using the same components. Thecapability for using the same components to construct a variety of RBCassemblies would, if available, offer many practical advantages,especially where the characteristics of a particular wastewater areincorrectly initially determined, or substantially change over time. Tothis end, the technology of my U.S. Pat. No. 4,729,828 was provided tointroduce modularity into RBC design considerations.

Though the technology of my '828 patent is very useful, it would bedesirable to improve such. For one thing, it would be desirable toimprove system versatility so that an assembled RBC comprised ofpreformed components can have a greater variety of differentconfigurations. In the '828 system, for example, the tank or troughvolume of each successive stage is determined by the interior length ofa preformed tank-defining section which has fastened at and across eachlongitudinal opposite end thereof a bulkhead-type member. For greaterversatility, the interior length of the trough of a single stage needsto be variable incrementally. Selected tank housing sections need to bejoinable adjacently without the need for a bulkhead-type memberpositioned between each pair of longitudinally adjacent tank housingsections. Outside support side walls of trough defining sections need tobe separate from, but associatable with, the trough defining sectionsthemselves in certain circumstances.

For another thing, the respective longitudinally extending individualshaft structures when located in each stage should be more readilylength adjustable and should be more readily, simply and reliablyconnectable with, and disconnectable from end adjacent, coaxial endshafts of shaft structures located in longitudinally adjacent stages sothat all shafts, as coaxially interconnected, rotate together yet bereadily connectable and disconnectable.

For another thing, it would be desirable for the assembled RBC to beoperationally more energy efficient so that less applied power,particularly electric power, would be needed in system operation forshaft rotation. In, for example, some RBC installations of the typetaught by my '828 patent, relatively large (and thus relativelyexpensive) amounts of electric power may need to be expended in rotatingthe shaft.

For another thing, it would be desirable for an RBC to be fittable intoan existing relatively confined structure (such as a building, pit,etc.) and to be readily assembled from prefabricated components, even byonly two men using simple tools.

The developing field of aquaculture brings new and additional challengesto wastewater treatment and to RBC structures useful in treatingwastewaters from such field. A desire for recirculated water and waterreuse for use in aquaculture production has developed which necessitatessolving the problems of achieving consistent water quality whileconserving the use of water and the energy required to maintain stablewater temperatures for continuous production at latitudes wheresubstantial environmental temperature variation is normal. Also,aquaculture facilities that employ more traditional fish productiontechniques employing only new water and require large wastewater flowsmay no longer be appropriate. This is especially true if the aquaculturefacility is located near desired markets where competing uses of landand water limit access to resources and require constraining demands onwastewater.

Each species of fish cultured requires an optimized water temperaturefor rapid growth. This temperature typically falls in the range fromabout 5° C. to about 40° C. Likewise, salinity influences fish cultureand typically falls in the range from 0 to about 40 ppt. Also, uniquedietary requirements for these cultured species can include proteincontents typically ranging from less than about 30% to greater thanabout 50%. Dietary protein ultimately leads to ammonia contamination ofthe culture water. Typically, those fish species which require a lowertemperature environment also require the highest dietary protein. Whenusing a biological filter, such as an RBC, both these conditions requirea relatively large contactor media surface area to assure sufficientbiological activity for purposes of achieving and maintaining a set ofdesired or necessary water quality conditions, particularly when waterrecirculation is contemplated. As temperatures fall, bacterialactivities slow, thus requiring increased medium surface area to obtainsufficient bacterial colonization to obtain desired levels of nutrientdestruction. Likewise, as the protein level in the feed increases,ammonia production increases, requiring increased medium surface area toobtain the requisite ammonia destruction.

With relatively stringent water quality parameters, such as totalammonia nitrogen (TAN) as low as 1.0 mg/l and nitrite nitrogen (NO₂—N)as low as 0.1 mg/l on the outlet from the wastewater treatment unit, RBCdesign specifications which will result in such output water parametersare little understood. RBC equipment and operating conditions haveheretofore commonly not been commercially available to readily satisfysuch stringent and/or variable circumstances. To permit or enhance theuse of RBCs in such demanding conditions and circumstances, it would bedesirable to have convenient and readily assembled or disassembledimproved components for use in RBC systems.

Particularly in aquaculture, the need is great for relatively low cost,economically operating RBC's that are comprised of relatively low cost,easily transported, handled and assembled components and that canachieve output water which meets stringent water quality parameters andso is recirculatable. A large user component of the aquaculture field iscomprised of small entrepreneurial and family farm establishments thatutilize existing structures as aquaculture facilities, such as garages,barns, idle livestock production buildings, warehouses, and the like. Anembodiment of RBC apparatus manufactured by the prior art techniques andcomponents, such as above indicated, proves extremely difficult tofabricate and use from the standpoints of cost, transportation, and userassembly in such small facilities. The problem is exacerbated by thefact that many of these facilities have a ceiling height of less thanabout three meters (about 10 feet). RBC components need to be smallenough for convenient transport and for assembly in such a structure byno more than two individuals.

It appears that, particularly in the aquaculture field, readilyassemblable RBC components and subcomponents that are low cost,adaptable for use in small space, and easily manipulated are needed andwould potentially enjoy wide usage.

SUMMARY OF THE INVENTION

More particularly, in one aspect, the present invention relates toimproved, variously configurable, rotating biological contactors (RBCs)which can, if desired, be comprised of multiple stages, and whichincorporate prefabricated modular-type components.

In another aspect, the present invention relates to prefabricatedmodular-type components which can be easily and simply utilized tofabricate various RBC structures.

In another aspect, the present invention relates to prefabricatedsubcomponents which can be assembled readily, simply and reliably intomodular-type components that are useful in RBC structures.

As those skilled in the art will readily appreciate, the variousprefabricated components and subcomponents here achieved need not all beincorporated into a single RBC embodiment. However, these components andsubcomponents permit one to design and assemble various RBC embodiments.Particularly after an RBC has been designed to work with a particularwastewater, these components and the subcomponents are particularly welladapted for movement into and location in a confined space or RBCinstallation site if desired and for ready fabrication and assembly intoan RBC by as few as two relatively unskilled individuals using simpletools. The advantage of these components and subcomponents is that a fewstandardized units provide the opportunity to not only design anindividualized kit for on site assembly of an RBC that has beenspecifically designed to meet the needs of most any wastewaterapplication, but also by simply adding, subtracting, or rearrangingcomponents and subcomponents, treatment performance can be enhanced.Moreover, the RBC structures made with or incorporating such componentsand subcomponents are sturdy, reliable, economical and easy to use andmaintain.

The subcomponents, components, and RBC structures provided here areversatile, easily handled and utilized, and are believed to makepossible the easy and convenient fabrication, achievement, andutilization of RBCs particularly in locations and in circumstances notpreviously convenient, or practical, for RBCs.

The novel and very useful RBC components here provided include, forexample:

(A) Trough (or tank) defining sections that usually include side walldefining portions for a trough. Preferably, a plurality of such sectionsmay be considered, if desired, to comprise, a trough section set. Troughsections of a set can have similar widths and depths, and are preferablyhemicylindrically configured so that, if desired, these trough sectionscan be employed in a single RBC, and can be arranged together in anadjacent, end-to-end relationship, longitudinally along a commonlongitudinal axis, so that, if desired, a longitudinally extendingtrough can be defined between adjacent pairs of the trough definingsections. Preferably, each opposite end of each trough section extendstransversely and perpendicularly. Side wall defining portions can beoriented perpendicularly (preferred) or inclined (relative to vertical)and characteristically have access apertures defined therein.Preferably, the trough sections of a set have similar respectivelongitudinal lengths, although trough sections in a set may have, ifdesired, various longitudinal lengths. Longitudinally adjacent troughsections are easily aligned and fastened together.

(B) Bulkheads for transversely extending across respective opposite endportions of a trough defining section.

A first type of bulkhead is adapted for locating at, across and adjacentto one end of a trough defining section, thereby to define an troughendwall. Preferably the bulkhead type has upper wall edge portions thatare about the height of the adjacent trough defining section. Preferablythe bulkhead type supports an adjacent trough end section in a stable orupwardly spaced relationship relative to an underlying generallyhorizontal support surface (such as a floor, ground, or other surface).Each bulkhead type may have aperture means defined therein for achievingfluid flow therethrough. Preferably, a longitudinally spaced butadjacent pair of the first type of bulkhead serve to define a stagelocated along the trough defined by at least one trough defining sectionin an RBC.

A second type of bulkhead is adapted for locating at, across andadjacently between a pair of longitudinally adjacent trough definingsections while permitting the respective interior surface configurationsof the adjacent respective trough sections to be longitudinallygenerally aligned and substantially longitudinally continuous, therebyto lengthen the trough length to be about the combined length of each ofthe trough sections. Preferably, the bulkhead supports the adjacenttrough section ends in upwardly spaced relationship relative to anunderlying generally horizontal support surface.

(C) Shaft assemblies adapted to extend longitudinally along thelongitudinal axis of a least one trough defining section or a pluralityof longitudinally adjacent, axially aligned trough defining sections.Each shaft assembly includes (a) a cross-sectionally rectangularmid-region, (b) a cross-sectionally circular end region at each oppositeend of the mid-region, and (c) first connecting means for coaxiallyjoining each end of the mid-region with one end of a different endregion. Each shaft assembly may optionally include (d) second connectingmeans for coaxially joining a pair of adjacent cross-sectionallyrectangular mid region sections. Typically, there is one shaft assemblyper RBC stage but a single shaft assembly can extend longitudinallythrough a plurality of longitudinally adjacent trough defining sections;a shaft assembly preferably has a length that is at least equal to thelength of an associated stage.

Preferably in an RBC embodiment a shaft structure such as hereinprovided extends longitudinally, perpendicularly and axially through thetrough defining portions, contactor members and paddle wheel assemblies.

Each shaft assembly is associated with bearing means for rotatablymounting and suspending each end region of a shaft assembly. Variousbearing means can be utilized. Each shaft assembly and bearing meansstill further includes support means for supporting each bearing meansrelative to one first type of bulkhead whereby, if desired, a shaftassembly can extend longitudinally and axially through a single troughdefining section and be rotatably supported at each of its respectiveopposite ends by a different first type of bulkhead.

A pair of bearing assemblies is preferably provided that can beconsidered to comprise a bearing block assembly. A bearing blockassembly can be provided at each end of a shaft assembly for associationwith each one of a pair of different, adjacent, coaxial shaft endregions, each end region being associated with a different one of a pairof longitudinally adjacent shaft assemblies. These bearing assembliesare in longitudinally aligned, coaxial relationship relative to eachother in a bearing block assembly.

Support means is provided for bearings. A support assembly is preferablyprovided for each of the bearing block assemblies and the supportassembly is preferably supported by an upper portion of a first type ofbulkhead. Preferably a structure means that is supported on or by afirst type of bulkhead. Preferably, the support means includes aplatform means upon which a bearing or bearing block assembly may rest.

Also, in a bearing block assembly, the respective bearing means of thispair of bearing assemblies are interconnected relative to one an otherso that when one shaft end region is associated with one bearingassembly, and the second shaft end region is associated with the otherbearing assembly, these respective shaft end regions rotate together sothat as one shaft end region rotates, the adjacent one shaft region alsorotates. Thus, a plurality of shaft assemblies if present in a given RBCare interconnected together in end-to-end, co-axially alignedrelationship, so that the shaft assemblies rotate together.

Preferably, in an RBC, the component shaft assembly (or shaftassemblies, as the case may be) is/are functionally connected with, androtatable by, a motor driven drive assembly which can be conventional.More preferably, this drive assembly includes a geared electric motormeans.

(D) Contactor drum. Here a contacting medium is preferably drumconfigured. A contact drum is generally cross-sectionally circularrelative to its axis and that has center portions that are each toextend over and about portions of the mid-region of a shaft assembly.Each contactor drum is an assembly that is at least in partprefabricated. A fully assembled contactor drum is adapted for rotationwith a shaft assembly while located in the trough of a trough-definingsection with the contactor drum assembly being in spaced, adjacentrelationship to transversely adjacent portions of the trough definingsection. If desired, a plurality of individual contactor drum assembliescan be employed in an RBC embodiment with preferably each contactor drumassembly being in longitudinally spaced relationship relative to othersthereof.

(E) Paddle wheel. Here a paddle wheel is preferably drum configured andis generally or grossly cross-sectionally circular relative to its axisand has center portions that are each adapted to extend over and aboutportions of the mid-region of a shaft assembly. Each paddle wheel is anassembly that is at least in part prefabricated. A fully assembledpaddle wheel is adapted for rotation with a shaft assembly while locatedin the trough of a trough-defining section with the paddle wheelassembly being in spaced, adjacent relationship relative to transverselyadjacent portions of an RBC embodiment with preferably each paddle wheelassembly being in longitudinally spaced relationship relative to othersthereof.

Preferably, the trough defined by a trough defining section and a firsttype of bulkhead at each end thereof is chargeable with a wastewater toan extent, if desired, such that up to about 50% of each of thecontactor drum assemblies and the paddle wheel assemblies may beimmersed in said wastewater. Preferably, each paddle wheel is adapted tobe rotatably driven by a fluid stream (either a gas, including air, or aliquid, including wastewater, or a mixture thereof). Thus, a shaftassembly is rotatable by either one or both of a connected powerhead andthe fluid stream.

The trough defining sections, the bulkheads, the shaft assemblies, thecontactor drum assemblies, and the paddle wheel assemblies are eachpreferably comprised of prefabricated subcomponents such as are taughtherein and that are useful in the assembly and operation of RBCembodiments, and these prefabricated subcomponents and the componentsassembled therefrom are believed to be inventive and to form portions ofthe present invention.

The novel and very useful RBC subcomponents here provided include, forexample:

(A) Subcomponents that in combination define a trough (or tank) definingsection as above identified. The subcomponents can include, for example,(a) a generally hemicylindrically configured central portion thatdefines a longitudinally extending trough, (b) side leg portions thatmay be associated at an end region of a side leg portion with a lateralside region of a central portion either integrally or detachably therebyto support the central portion in a generally horizontal orientation. Aplurality of such subcomponent portions may be considered, if desired,to comprise, a set for achieving one or more trough defining sections.Trough sections defined by subcomponent portions of a set can havesimilar widths, depths and heights, and are preferably individuallyconfigured so that, if desired, the trough sections defined by acombination of the subcomponent portions can be employed in a singleRBC.

Preferably such trough sections can be arranged together in an adjacent,end-to-end relationship, longitudinally along a common longitudinalaxis, thus defining, if desired, a longitudinally extending troughbetween adjacent pairs of such trough defining sections. Preferably,each opposite end of each trough section defined by a combination ofcentral and side wall defining subcomponent portions extendstransversely and perpendicularly relative to the so defined troughsection. Preferably, the trough sections defined by a set have similarrespective longitudinal lengths, although trough sections in a set mayhave, if desired, various longitudinal lengths.

(B) Subcomponents that in combination define a bulkhead structure asabove identified. The bulkhead structure can comprise a first type or asecond type of bulkhead as above identified for transversely extendingacross respective opposite end portions of a trough defining section.

One present preference is to provide bulkhead subcomponents that can beinterfacially associated together to comprise a layered or laminatedbulkhead structure.

(C) Subcomponents that in combination define a shaft assembly as aboveidentified.

A shaft assembly can be comprised of various components. For example,the mid region and the opposite end regions of a shaft assembly can beprovided in various lengths and transverse widths, and various first andsecond connecting means can be provided.

Various bearing assemblies can be utilized with a shaft assembly.

(D) Subcomponents that in combination define a contactor drum assemblyas above identified. A presently preferred arrangement is to providesubcomponents that include half portions of a contactor drum assemblythat matingly engage to comprise the contactor drum assembly with theassembly located at its center about the mid region of a shaft assembly.

(E) Subcomponents that in combination define a paddle wheel assembly asabove identified. A presently preferred arrangement is to providesubcomponents that comprise paddle wheel portions that matingly engageto comprise a paddle wheel assembly with the assembly located at itscenter about the mid-region of a shaft assembly.

The trough defining sections, the bulkheads, the shaft assemblies, thecontactor drum assemblies, and the paddle wheel assemblies can be, andpreferably are, if desired for small environments and assembly by notmore than two men, each be comprised of prefabricated subcomponents suchas are taught herein and that are useful in the assembly and operationof RBC embodiments. These prefabricated subcomponents and the componentsassembled therefrom are believed to be inventive and to form portions ofthe present invention.

Hence, in one aspect, as above indicated, the present invention relatesto a group of novel and very useful individual pre-fabricated componentsand subcomponents that are adapted to be assembled variously and toco-act together in components or in RBCs, thereby to produce a desiredembodiment of an improved RBC structure of the present invention.

The subcomponents and the components can be variously connected togetherto produce novel and very useful RBCs. The components, and thecombinations of subcomponents, can, if desired, be combined with othercomponents and subassemblies to achieve fabrication of an RBC embodimentwhich is novel and very useful. The subcomponents and the componentscomprised thereof are versatile, durable, simply assembled, andvariously usable particularly in fabricating an RBC structure. Aresulting RBC structure is itself novel and very useful.

Preferably, the individual subcomponents are preferably substantiallyunitary in structure, and are readily and simply interconnectable withone another as structural building units to comprise components andRBCs.

As those skilled in the art will readily appreciate, the components andthe subcomponents are preferably connected together by variousconventional means during assembly and fabrication of an RBC, such ashereinbelow illustrated or otherwise as desired. Examples of connectormeans include screws, nut and bolt assemblies, brackets, braces, and thelike. Preferably the connector means are comprised of plastic or metal,most preferably stainless steel.

As those skilled in the art will readily appreciate, preferably andcharacteristically, prefabricated subcomponents and components areindividually portable. Such are conveniently comprised of metal and/orplastic materials, preferably materials that after fabrication areinert, durable, insoluble, non-toxic, and non-corrosive. In the casewhere food production is involved, the construction materials should beof food contact grade. If desired, a subcomponent or component, such asin a trough-forming section, can incorporate or contain embedded, orassociated, metal subcomponents for rigidification or structuralenhancing purposes. Various plastic and metal materials can be used infabricating components, as those skilled in the art will readilyappreciate. A presently preferred plastic comprises a thermosettableplastic such as a fiberglass reinforced polyester, like a polyethyleneterephthalate, or a thermoformable plastic such as a polyvinylchloride.A presently preferred metal comprises a stainless steel.

In an RBC embodiment of the invention, the various components andsubcomponents are variously configurable and constructable, as thoseskilled in the art will appreciate. Preferably, each of theprefabricated subcomponents is substantially unitary in structure,thereby to facilitate durability and enhance ease of assembly ordisassembly with other components and subcomponents of an RBCembodiment. The components and subcomponents are preferably readily andsimply interconnectable, preferably disconnectably, with one another asstructural subunits so as to be conveniently useful and functional increating and operating an RBC embodiment for use in treating aparticular wastewater (preferably based on initially determined RBCdesign criteria for that wastewater).

An embodiment of an RBC structure is preferably assembled from aselected combination of preliminarily fabricated components andsubcomponents, such as are provided by the present invention, so as tomeet a preferably preliminarily identified and designed set offunctional operating parameters. Thus, preferably through an initialselection of a particular set of functional operating parameters, and ofparticular such pre-fabricated components and subcomponents, a desiredor chosen particular structural assembly for an RBC system is achieved.

In an assembled and functional RBC embodiment, as above indicated, theregion between an adjacent pair of bulkheads is preferably adapted todefine a stage, and, if desired, an RBC embodiment can be comprised of aplurality of stages that are arranged in longitudinally adjacentrelationship relative to one another along the tank. More than onetrough defining section can be located between a pair of longitudinallyadjacent bulkheads.

In operation, as those skilled in the art appreciate, wastewater beingtreated in an RBC embodiment is illustratively and typically orconveniently charged to the RBC embodiment adjacent to an end regionthereof, and advances (flows) longitudinally through the RBCprogressively from one stage to another (if the RBC utilizes more thanone stage), and exits adjacent to an opposite end region thereof. Duringoperation, the contactor members, and, if present, the paddle wheelmembers, are rotated on their common shaft means. An RBC embodiment isassociated with conventional means for conveying untreated wastewater toand treated wastewater therefrom.

By selecting component dimensions, such as the diameter and thelongitudinal length (relative to the trough defined by the troughdefining sections or relative to stages defined by the sections andbulkheads), the contactor drum assembly and the paddle wheel assemblyare enabled to participate in various configurations of an RBCembodiment. The contactor drum and paddle wheel embodiments arepreferably circular.

In a presently preferred RBC embodiment, a paddle wheel subassembly hasvanes that are responsive to fluidic pressure locally appliedthereagainst so that resultingly the involved paddle wheel is rotatablydriven thereby. The fluidic pressure can be gas (preferably air), water(preferably wastewater) or a mixture of both. The fluidic pressure, whenutilized, can comprise either the sole power source for rotating theshaft structure of the RBC, or a portion of the power source. If thelatter, then the fluidic pressure can be utilized in combination withanother power source.

Various power sources and power transfer arrangements can be utilized.Typically, when a power source such as an electric geared motor isemployed, it is functionally associated with the shaft means by means ofa conventional power transfer means.

In some RBC embodiments, and in some operating conditions and locations,it has been found that the need for a geared electric motor to powerrotation of assembled shaft sections and shaft associated components canbe partially or even completely eliminated by equipping the RBC with atleast one paddle wheel mounted preferably coaxially adjacent to acontactor on a shaft section. The force of water and/or air against theblades of the paddle wheel(s) provides power for rotating the shaftstructure and shaft associated components. For example, in anapplication where wastewater is input into and flows through an RBCembodiment at a relatively rapid rate, a portion of the wastewater inthe receiving stage can be deflected against paddle wheel blades in thatstage, thereby reducing the amount of electric power required for shaftturning.

Another bulkhead member of the first type, particularly if locatedintermediately between a pair of longitudinally adjacent tank formingsections, preferably has at least one porthole defined therethrough.Each porthole may optionally be provided with a porthole closure. Eachporthole closure may optionally be adjustable or removable so that theeffective size of an associated porthole is adjustable.

Contactor members and paddle wheels for RBCs appear to have been knownto the prior art. However, so far as now known, nothing in the prior artdiscloses or suggests the structures achieved presently.

One new and very useful class of contactor drum assemblies is providedby the present invention. Such a contactor drum assembly has, whenassembled, a drum-like configuration, and which when disassembledcomprises approximately two halves that cooperatively engage along adrum diameter and fit over and about a shaft means that extendsperpendicularly and axially therethrough.

One new and very useful class of paddle wheel assemblies is provided bythe present invention. Such a paddle wheel assembly has a generalcylindrical configuration with access to paddle wheel blades being alongcircumferential portions. This paddle wheel assembly is comprised of twoportions which when assembled are brought together about a shaft meansthat extends perpendicularly and axially therethrough.

A new and useful class of trough-defining sections is provided whereinthe sidewalls are opposed to each other integral generallyperpendicularly downwardly from the top side portion of each section'smedial portions, and each side wall has a central aperture definedtherein which permits access therethrough for purposes of assembly ofadjacent components, such as other trough-defining sections, bulkheads,or the like with screws, nut and bolt assemblies or the like.

Another new and useful class of trough-defining sections is providedwherein at least one and optionally both of the sidewalls are detachablefrom each of the trough-defining sections thereby to providetrough-defining section versatility for purposes of RBC assembly,maintenance, or the like, as taught herein.

If desired, an embodiment of an RBC of the present invention can bepreceded by upstream wastewater processing equipment or succeeded bydownstream wastewater processing equipment.

The individual components utilized in the present invention areeconomical to fabricate, reliable, durable, sturdy, and easy and simpleto associate together.

The embodiments of RBC's produced in accord with the teachings of thepresent invention are economical, easy to assemble, reliable, durableand sturdy.

One object of this invention is to provide RBC embodiments comprised ofpreformed components and subcomponents that have a maximum amount ofutility and utilization.

Another object is to achieve preformed components that aretransportable, that are able to be assembled into RBC embodiments byonly one or two men, if desired.

Another object is to achieve components that enable the assembly and useof an RBC embodiment in a confined location, such as a room having arelatively low ceiling, or an open cavity of limited depth, such as anold machine access pit, or the like.

Another object is to provide modular RBC systems which are easy to use,assemble and maintain, and which are reliable, economical and welladapted for usage in substantially all situations where modular RBCsystems can be employed for wastewater treatment.

Another object is to provide improved modular RBC apparatus andcomponents that are well suited if desired for use in pilot studies andthe like of the type where RBC apparatus can be varied in structuralconfiguration, thereby to increase the capability and capacity toevaluate and to fine-tune a given installation design, or the like, asthose skilled in the art may desire to achieve.

Another object is to provide in RBC apparatus the capacity for providinga modifiable system which can be structurally altered or adjusted,including expanded or contracted, so that, as, for example, a givencommunity wastewater treatment problem changes with community growth ordecline, industrial growth or decline, or the like, an initial RBCapparatus can be expanded, contracted, and/or modified without having toreplace the entire original RBC apparatus, thereby achieving economies.

Another objective is to provide the capacity for a community to buildplant that incorporates an RBC for treatment of wastewater with an RBCdesign such that the immediate needs of the community are met at aparticular acceptable cost while yet preserving the capacity of thatcommunity to meet different needs at a later date without having tobuild entire new plant, thereby reducing initial installation costs,operating costs, and even subsequent operation costs.

Another object is to provide a RBC apparatus that is adapted for usewithin the recirculating water aquaculture community, that is suitablefor satisfying the needs dictated by the requirements for maintainingdesirable water quality parameters, and that can be employed for theeconomical production of a wide variety of commercially importantaquaculturable species.

Other and further objects, aims, features, purposes, advantages,embodiments, and the like will be apparent to those skilled in the artfrom the teachings of the present specification taken with theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of an illustrative embodiment of amultistage rotating biological contactor of the present invention whichis comprised of an assembly of selected prefabricated components such asare provided by this invention;

FIG. 2 is an exploded perspective view of an alternative embodiment of afirst stage of the rotating biological contactor embodiment shown inFIG. 1 with mid-portions of the shaft section being broken away; andwith the middle trough section and one drum-like contactor member beingeliminated;

FIG. 3 is a partial exploded perspective view of the shaft bearing blockassembly of the rotating biological contactor embodiment shown in FIG. 1in association with the end region of the shaft;

FIG. 4 is an exploded perspective view of the bearing block assembly ofthe rotating biological contactor embodiment shown in FIG. 1 and FIG. 3which interconnects coaxially with respective adjacent end of each of athe pair of coaxial shafts employed in the first and the second stagesof the rotating biological contactor embodiment shown in FIG. 1, theshafts being broken away adjacent to each of their respective shaftends;

FIG. 5 is a transverse sectional view through the FIG. 1 rotatingbiological contactor embodiment showing an end elevational view of thefirst stage contactor drum with portions of its side wall being brokenaway;

FIG. 6 is an enlarged, fragmentary, perspective, detail view of theinterior region of one arrangement for corrugated layers in a FIG. 5contactor drum;

FIG. 6A is an enlarged, fragmentary, perspective detail view of theinterior region of an alternative arrangement for corrugated layers in aFIG. 5 contactor drum;

FIG. 7 is an enlarged, fragmentary, perspective, detail view of portionsof the paddle wheel structure shown in FIG. 1 with one end wall thereofbeing removed;

FIG. 8 is a perspective view of an alternative the paddle wheelstructure with portions of one end wall thereof being broken away;

FIG. 9 is a transverse sectional view taken through the FIG. 1embodiment showing a side elevational view of an alternative embodimentof a paddle wheel structure with an end wall thereof removed;

FIG. 10 is an enlarged fragmentary detail view of the alternative paddlewheel of FIG. 9 showing the manner in which paddle wheel bladesassociate with a hub member axially located and positioned between theblade end plates;

FIG. 11 is a diagrammatic view of the first stage of the rotatingbiological contactor embodiment shown in FIG. 1 in functionalassociation with both an electric power drive subassembly and a fluidicpower drive;

FIG. 12 is an end elevational view illustrating the profile of the endbulkhead of the FIG. 1 rotating biological contactor embodiment;

FIG. 13 is a view similar to FIG. 12 but illustrating the profile of aninterstage bulkhead of the type used in the FIG. 1 rotating biologicalcontactor embodiment;

FIG. 14 is a view similar to FIG. 12 but illustrating the profile of theopposite end bulkhead of the FIG. 1 rotating biological contactorembodiment;

FIG. 14A is a view similar to FIG. 12 but illustrating the profile of analternative interstage bulkhead usable in the FIG. 1 rotating biologicalcontactor embodiment;

FIG. 14B is a view similar to FIG. 12 but illustrating an alternativeend bulkhead usable in the FIG. 1 rotating biological contactorembodiment;

FIG. 15 is an enlarged, fragmentary, perspective, detail view of aportion of a bulkhead structure suitable for use in the rotatingbiological contactor embodiment of FIGS. 1 and 2, some portion thereofbeing broken away;

FIG. 16 is a perspective exploded view of an alternative embodiment(compared to FIG. 2) of a shaft assembly usable in the practice of thepresent invention;

FIG. 17 is a perspective exploded view of the shaft assembly of FIG. 2illustrating one manner of functionally associating this shaft assemblywith a powerhead;

FIG. 18 is a perspective exploded view of an alternative embodiment(compared to FIG. 16) of a shaft assembly usable in the practice of thepresent invention;

FIG. 19 is a perspective exploded view of an alternative embodiment(compared to FIG. 2) of a shaft assembly usable in the practice of thepresent invention;

FIG. 20 is an exploded perspective view of an alternative embodiment(compared to the embodiment shown in FIGS. 1 and 2) of a trough definingsection comprised of two portions;

FIG. 21 is a left side (relative to FIG. 20) elevational view of thetrough defining section of FIG. 20;

FIG. 22 is a right side (relative to FIG. 20) elevation view of thetrough defining section of FIG. 20 separated from the right side supportstructure;

FIG. 23 is an enlarged, fragmentary, detail view illustrating the mannerin which two trough defining sections such as shown in FIG. 20 areconnectable together in end-to-end adjacent relationship;

FIG. 24 is a perspective view of a bulkhead that is usable incombination with one end of a trough defining section combination suchas shown in FIG. 20;

FIG. 25 is an exploded perspective view similar to FIG. 20 but showingan alternative embodiment of a trough defining section comprised to twoportions;

FIG. 26 is a perspective view of a bulkhead that is similar in edgeprofile to that shown in FIG. 24 but which is suitable for connectionbetween two adjacent ends of a pair of trough defining sectioncombination to provide support and to extend the internal length of atrough defined by this pair of adjacent trough defining sections;

FIG. 27 is an exploded perspective view of an alternative troughdefining section embodiment (compared, for example, to the embodimentshown in FIG. 25) where the trough mid region is separately from each ofthe opposing side supports of the trough defining section;

FIG. 28 is a perspective view of the bracket type employed in theassembly of rotating biological contactor embodiments such as shown inFIGS. 1 and 2;

FIG. 29 is a view similar to FIG. 6 but showing the bracket of FIG. 28turned 90° in a contactor drum relative to its orientation in thecontactor drum employed in the rotating biological contactor embodimentsof FIGS. 1 and 2;

FIG. 30 is a view similar to FIG. 5 but showing a preferred manner inwhich the brackets of FIG. 28 oriented as shown in FIG. 29 are connectedto an end plate of the contactor drum assembly;

FIG. 31 illustrating a contactor drum such as shown in FIG. 30 whereinthe end plates 54 are each assembled together along their commondiameter from subcomponent half portions using a connecting plate, oneend plate being illustratively shown in exploded relationship relativeto the contactor drum core and at an optional rotation of 90 degrees;

FIG. 32 is a side elevational view of an alternative embodiment of acontactor drum that is assembled from subcomponent half-portions as inFIG. 31 but wherein six brackets of the type shown in FIG. 28 located atcircumferentially equally spaced positions are employed;

FIG. 33 is a fragmentary, perspective view illustrating one manner inwhich diametrical edge portions of the end plates of a contactor drumsuch as shown in FIG. 31 may be associated together;

FIG. 34 is a fragmentary, perspective view illustrating a second mannerin which diametrical edge portions of the end plates of a contactor drumsuch as shown in FIG. 31 may be associated together;

FIG. 35 is a fragmentary, perspective view illustrating a third mannerin which diametrical edge portions of the end plates of a contactor drumsuch as shown in FIG. 31 may be associated together;

FIG. 36 is an enlarged, fragmentary perspective, detail viewillustrating the manner in which the connection illustrated in FIG. 35is accomplished with radially extending nut and bolt assemblies;

FIG. 37 is a view similar to FIG. 9 but showing an alternativeembodiment of the paddle wheel of FIG. 8;

FIG. 38 is an enlarged, exploded, fragmentary view illustrating themanner in which the paddle wheel blades associate with a hub member inthe paddle wheel embodiment of FIG. 8;

FIG. 39 is a diagrammatic vertical sectional view through a paddle wheelin an operating RBC embodiment illustrating one technique for applying afluidic force to surface portions of the paddle wheel's blade members;

FIG. 40 is a diagrammatic view similar to FIG. 39 but illustrating asecond technique for applying a fluidic force to surface portions of thepaddle wheel's blade members;

FIG. 40A is a diagrammatic view similar to FIG. 39 but illustrating athird technique for applying a fluidic force to surface portions of thepaddle wheel's blade members;

FIG. 41 is a fragmentary perspective view illustrating construction ofan alternative embodiment of a paddle wheel assembly;

FIG. 42 is a perspective view of the paddle blade spacing and supportingmember utilized in the paddle wheel of FIG. 41;

FIG. 43 is an exploded perspective view of a combination of twocontactor drums and an intervening paddle wheel with a shaft assembly,each component being assembled from subassemblies, this combinationbeing comparable in part to the combination shown in the stages of theFIG. 1 rotating biological contactor embodiment;

FIG. 44 is an exploded perspective view of an RBC embodiment thatincorporates a combination of a contactor drum and a paddle wheel with ashaft assembly, each component being assembled from subassemblies, thebearing assembly being shown in phantom, this combination beingcomparable in part to the RBC embodiment shown in FIG. 2;

FIG. 45 is an exploded perspective view of an RBC embodiment whichincorporates one trough defining section of the type shown in FIG. 27,one contactor drum assembly of the type shown in FIG. 31, one shaftassembly of the type shown in FIG. 19, and a pair of bulkheads of thetype shown in FIG. 24;

FIG. 46 is an illustrative side elevational view of a rotatingbiological contactor embodiment located in a pit, this rotatingbiological contactor incorporating the trough defining section of FIG.27 (but without the side walls), and the combination of contactor drumsand paddle wheel of FIG. 39, the adjacent ground region being shown insection; and

FIG. 47 is a vertical, transverse sectional view through the mid-regionof the paddle wheel in the RBC embodiment of FIG. 46.

DETAILED DESCRIPTION (A) Illustrative RBC Embodiments

Referring to the drawings, there is seen in FIG. 1 an illustrativeassembled embodiment 25 of the inventive RBC. The RBC embodiment 25includes three longitudinally adjacent, successive, functionallyinterconnected stages or wastewater treating compartments 26, 27, and28. The internal and external side walls of each stage 26, 27, and 28are each defined by three unitary, preformed and interconnected troughor tank sections 30, 31, and 32, respectively, which are eachsubstantially identical to one another and arranged in longitudinallyadjacent, aligned, interconnected relationship.

Referring to FIG. 2, an exploded view of an alternative RBC embodiment29 is shown which incorporates a single stage. RBC embodiment 29 issimilar to stage 26 of RBC embodiment 25 except that the middle troughsection 31 is eliminated and one contactor member 53 (structuredescribed below) is eliminated so that RBC embodiment 29 has a lengththat is approximately defined by trough sections 30 and 32. Componentsin RBC embodiment 29 which correspond to components in stage 26 in RBCembodiment 25 are similarly numbered for convenience in identification.Embodiment 25 or embodiment 29 can be provided with a cover or the like,not shown, if desired.

The medial wall portions 33 (see FIG. 2) of each trough section 30 and32 preferably each have a hemicylindrical configuration. Various troughdefining sections and subcomponents can be employed and are exemplifiedand described below.

What can be considered to be the open, vertical, opposed ends of therespective interconnected trough sections 30, 31 and 32 in each stage26, 27 and 28 of RBC embodiment 25, and also the open vertical opposedends of single stage 29 (FIG. 2) containing tank sections 30 and 32 areeach provided with a bulkhead generally designated as 39. In theillustrative embodiments 25 and 29, the bulkheads 39 are illustrativelysubstantially identical to one another, but, if desired, variousbulkhead structures can be employed. Various exemplary bulkheads aredescribed below.

Two contactor drum assemblies 53 are provided in each stage 26, 27 and28 of RBC embodiment 25, and one contactor drum assembly 53 is providedin the single stage of RBC embodiment 29. The contactor drum assemblies53 are here preferably and illustratively substantially identical to oneanother, but various contactor structures can be employed, if desired.However, if as in the prior art, a known type of preformed contactorstructure is employed, and the contactor structure is associated with adrive shaft, then such an assembly must be preliminarily formed and theresulting assembly, because of bulk and weight considerations, must belifted, moved into a desired position and engaged with a shaft by ahoist or the like. Such a prior art assembly is not suitable for usagewhen space is limited or where assembly of an RBC is to be accomplishedby not more than two men with simple tools. Hence, a contactor drumstructure 53 that is comprised of subcomponents that can be simplyassembled at an RBC installation site, such as presently achieved, andas exemplified and described below, is presently preferred for use in anRBC embodiment in accord with the practice of the present invention.

In RBC embodiment 25, one paddle wheel assembly 60 is preferablyprovided in each stage 26, 27 and 28, as shown in FIG. 1, and, in RBCembodiment 29, one paddle wheel assembly 60 is preferably provided inthe single stage. The paddle wheel assemblies 60 in RBC embodiments 25and 29 are here preferably and illustratively substantially identical toone another, but, if desired, alternative paddle wheel structures can beemployed, if desired. The paddle wheel assembly 60 is presently apreferred component for use in the practice of the present invention.However, if as in the prior art, a known type of paddle wheel structureis employed, and the paddle wheel structure is associated preliminarilywith a drive shaft, then the resulting assembly, because of bulk andweight considerations, must be lifted and moved into a desired positionby a hoist. Such a prior art assembly is not suitable for usage whenspace is limited or where assembly of an RBC is to be accomplished bynot more than two men with simple tools. Hence, a paddle wheel assembly60 that is comprised of subcomponents that can be simply assembled at anRBC installation site, such as presently achieved, and as exemplifiedand described below, is presently preferred for use in an RBC embodimentin accord with the practice of the present invention.

Each of the stages 26, 27, and 28 of RBC embodiment 25 and the stage ofembodiment 29 is provided with a combination of sectionalized shaftassembly 76, bearing assemblies, and bulkhead support assemblies, suchas shown, for example, in FIG. 2 and as described below. One shaftassembly 76 is preferably provided for each stage. The shaft assemblies76 are here preferably and illustratively substantially identical to oneanother, but, if desired, alternative shaft assemblies can be employed.The shaft assembly 76 is presently a preferred component for use in thepractice of the present invention. However, if as in the prior art, aknown type of shaft assembly is employed, the shaft assembly may be veryexpensive and may be need to be preliminarily associated with othercomponents, such as a contactor drum assembly or a paddle wheelassembly, and then the resulting assembly combination, because of bulkand weight considerations, must be lifted and moved into a desiredposition by a hoist or the like. Such a prior art assembly is notsuitable for usage when space is limited or where assembly of an RBC isto be accomplished by not more than two men with simple tools. Hence, ashaft assembly 76 with associated bearing assemblies and bulkheadsupport assemblies that can be assembled at an RBC installation site,such as presently achieved, and as described below, is presentlypreferred for use in an RBC embodiment in accord with the practice ofthe present invention.

Relative to RBC embodiment 25, to assemble one stage, such as stage 26,two contactor drum assemblies 53 and one paddle wheel assembly 60 areutilized, in accord with a preferred practice of this invention, and asfurther described below. The components are assembled and concurrentlyassociated with the mid-region 77 of a now preferred shaft assembly 76.Various techniques of assembly can be employed. Presently preferredtechniques are described herein.

Various RBC embodiments can be assembled from components andsubcomponents provided by this invention. These components can beprefabricated or comprised of prefabricated subcomponents. Although forconvenience, illustrative RBC embodiments 25 and 29 are comprised ofcomponents such as, for example, the trough defining sections 30, 31 and32. the bulkheads 39, the drum contactors 53, the paddle wheels 60 andthe shaft assemblies 76, it will be appreciated that each of thesecomponents, if desired, can be comprised of assembled subcomponents,such as described herein below and as shown in accompanying FIGS. 1 and2, for example. In general, an RBC embodiment, in accord with thisinvention, usually incorporates (a) at least one trough defining housingsection, (b) at least two bulkhead members, (c) at least one a rotatableshaft assembly with bearing and support means, (d) at least onecontactor drum, and (e) power means for rotating at least one shaftassembly. The power means usually involves either (a) a geared electricmotor, or (b) at least one paddle wheel with associated paddle bladeimpelling means, or (c) both (a) and (b).

An RBC embodiment can incorporate more than one housing section witheach housing section including a longitudinally extending troughdefining portion. When more than one housing section is used, theadjacent sections are joined together so that their trough definingsections have their respective defined troughs in longitudinally alignedrelationship.

An RBC embodiment incorporates at least two bulkheads, each one beingdisposed across a different opposed end of a trough defined by one ormore housing sections.

An RBC embodiment incorporates a shaft means that extends longitudinallythrough the so defined troughs, the shaft means including bearing meansand bearing means support means located at the bulkheads.

An RBC embodiment includes at least one contactor drum that isassociated with the shaft means and is located at least partially in atrough.

An RBC embodiment includes power means for rotating the shaft means.

Preferably, an RBC embodiment includes at least one paddle wheelassembly which augments or replaces another power means, such as anelectric motor, and the paddle wheel assembly includes auxiliarycomponents that enable a fluid stream to be directed against blades ofthe paddle wheel assembly, thereby to rotate the paddle wheel and theshaft means which is associated with the paddle wheel and also at leastone contactor drum which is also associated with the shaft means. Atleast one of the components of an RBC embodiment, particularly acontractor and/or a paddle wheel, is comprised of prefabricatedsubcomponents such as provided here. Preferably the components and thesubcomponents are assemblable with one another at an RBC installationsite. Preferably the assembly is accomplishable by no more than two menusing simple tools.

(B) Trough Defining Components and Subcomponents

In embodiment 25, each trough section 30, 31, and 32 has, exteriorly of,but adjacent to, each side of its medial, trough defining wall portions33, a pair of opposed side wall portions 34. At least one of these sidewall portions is unitarily associated with the trough defining portion,each unitarily associated therewith. Each side wall portion 34 isgenerally flat and is preferably perpendicularly oriented.

Each side wall portion 34 includes access apertures; thus, for example,each side wall is preferably comprised of two longitudinally adjacent,spaced, parallel legs 34A and 34B (see FIG. 2) separated medially by anopen gap or relatively large aperture 37. The upper and the lowerportions of the legs 34A and 34B are integrally joined together byvertically adjacent, spaced, parallel cross braces 34 D and 34E. Eachside wall 34 extends downwardly from a different opposed upper side edgeportions of the medial wall portions 33, and, in the trough sections 30,31 and 32, the respective side walls 34 are each integrally associatedwith the medial wall portions. Opposite end regions of each troughsection 30, 31 and 32 extend generally perpendicularly.

Trough sections can be comprised of a metal, preferably non-corroding,or preferably an insoluble plastic, such as a thermosetting plastic likea glass fiber filled polyester or the like, or a thermoformable plasticsuch as a polyvinylchloride or the like. Combinations and mixtures ofmetals and plastics can be employed. For ease in assembly, combinationsand subcomponents that are relatively light in weight are preferred.

The large aperture 37 defined in each side wall portion 34 permitsconvenient assembling or disassembling of tank sections 30, 31, and 32and of RBC embodiment 25, enables access to bottom regions of tanksections 30, 31, and 32 and to side regions of bulkheads 39, and thusavoids what could otherwise be difficult, sometimes otherwise unsolvableconstruction and maintenance problems which can arise particularly in alimited environmental space. Without aperture 37, an assembly orsubassembly of an RBC embodiment 25, for example, might have to beelevated in order to, for example, carry out component assembly and RBCfabrication at a site which has insufficient overhead clearance for suchan elevation. Each aperture 37 can be configured as desired, but is hereillustratively and preferably rectangular. A door (not shown) may beprovided for each aperture 37, if desired.

In each trough section 30, 31, or 32, a relatively small, rectangular,horizontally oriented, flat top 38 interconnects integrally thegenerally opposed (relative to the other thereof), longitudinallyextending straight upper end portions of each medial wall portion 33with the longitudinally extending straight upper end portions of eachadjacent exterior side wall 34. If desired, the walls 33, 34 and the top38 can be arranged to have various alternative shapes and spatialorientations.

The respective opposite end edge portions of each tank section 30, 31,and 32 are provided with an out turned or down-turned (depending on andrelative to the interior surface location of the medial wall portion33), continuously extending flange 36 (an in-turned flange, not shown,would be likely to cause the collection of solids behind each flangeinside a trough section). Longitudinally adjacent trough sections areconveniently bolted together using adjacent flanges 36 and nut and boltassemblies preferably with sealant deposited between adjacent flanges36.

While trough sections of different lengths (but of common widths) aretheoretically feasible for use in an RBC embodiment, trough sections offixed length are here preferred because flexibility of RBC design isthereby enhanced, as desired. For example, by fixing the longitudinallength to each trough section 30, 31 and 32 at 0.7 meters (about 24inches), restricting the longitudinal thickness of each of the contactordrum members 53 to either about 0.3 meters (about 12 inches) or about0.6 meters (about 24 inches) and restricting the longitudinal thicknessof each paddle wheel 60 to about 0.3 meters (about 12 inches),flexibility in assembly design is enhanced. For instance, in a designhaving three trough sections per stage (about 72 inches in longitudinallength), by using two contactor drum members 53 of each about 24 inchesin longitudinal length per stage 26, 27, 28, one located on either sideof the paddle wheel 60 (a combined width of about 60 inches), there isprovided 6 inches at each end of a stage assembly which is useful forachieving space for the bearing assembly 84 and support shelf structure47 thereby to keep the contactor drum 53 on each side on the paddlewheel 60 from rubbing against a bulkhead 39. It also provides a littlespace between two longitudinally adjacent stages such as stages 27, 28or stages 26, 27 for a user to have access to the bearing assembly 84(described below) for equipment assembly or maintenance purposes. Also,this arrangement allows for the paddle wheel 60 to be replaced by acontactor drum 53 if, for example, it is desired to provide only gearedmotor propulsion for all interconnected shaft assemblies 76 withoutaltering general assembly dimensions. This arrangement is, for example,illustrated in FIG. 45. For RBC embodiments in accord with the presentinvention, contactor drum longitudinal widths of about 24 inches areconvenient and commonly preferred. For purposes of convenience in theaccompanying Figures, the contactor drum widths are generally depictedas having narrow widths, for example, widths of perhaps about 12 inchesin relation to other components. In general, the exemplified componentsof an RBC embodiment should not be regarded as being drawn to scale.

Various structures and arrangements for a trough forming section can beutilized. For convenience and versatility in fabrication of an inventiveRBC structure, a trough section, such as the above described troughforming section 30, is separated into two portions, such as shown, forexample, in FIG. 20, where a side wall 34.1 is formed separately fromthe medial wall portion 33.1 in a trough forming section 30.1. Theopposing side wall 34.2 (relative to side wall 34.1) remains integrallyformed with the opposite side of the medial wall portion 33.1, as in thetrough section 30. Here, the upper opposite end portions of side wall34.1 are each configured to slidably engage with and between upperopposite side portions of the adjacent medial wall portion 33.1 with thetop flattened edge portion of the side wall 34.1 being nestably receivedbeneath the top flattened edge portion of the adjacent side portion ofthe medial wall portion 33.1. To rigidify and stabilize the engaged sidewall 34.1 relative to the medial wall portion 33.1, nut and boltassemblies 42 or the like can be longitudinally extended through alignedapertures defined between the assembled medial side wall 33.1 and theside wall 34.1, as illustrated, for example, in FIG. 23. Opposite endportions of a section 30.1 are preferably configured, as shown, forexample, FIGS. 21 and 22, so as to facilitate an assembled engagement oflongitudinally adjacent trough form ing sections 30.1 together.

An alternative trough forming structure comprised of a side wall 34.1′that is formed separately from the medial wall portion 33.1′ in a troughforming section 30.1′ is illustrated, for example, in FIG. 25. In thetrough forming section 30.1′, the opposing side wall 34.2′ (relative toside wall 34.1′) remains integrally formed with the opposite side of themedial wall portion 33.1′. Here, the upper opposite end portions of theside wall 34.1′ are configured to engage upper side portions of theflange 36′ that is provided on one end of the medial wall portion 33.1′.A downturned and inturned flange on the upper outside edge of the medialwall portion 33.1′ is adapted to be adjacent the upper outside edgeregion of the side wall 34.1′ during engagement of side wall 34.1′ withmedial side wall portion 33.1′. To rigidify and stabilize the engagedside wall 34.1′ relative to the medial wall portion 33.1′, nut and boltassemblies 42 or the like (not detailed) can be longitudinally extendedthrough aligned apertures defined between the assembled and adjacentportions of the medial side wall 33.1′ and the side wall 34.1 (see FIG.23, for example). To engage longitudinally adjacent trough formingsections 30.1′, the flange 36′ is employed in combination with the sidewalls 34.1′ and 34.2′ using nut and bold fastening means or the like,not detailed.

An illustrative trough defining section 30.6 is provided as shown inFIG. 27 wherein the medial side wall portion 33.6 is separate from, butconnectable with, each of the opposing side legs or walls 34.6 and 35.6.The medial side portion 33.6 can be used in an RBC assembly without theside legs when the medial side portion 33.6 is utilized in a cementdefined cavity such as illustrated, for example, in FIGS. 46 and 47.

(C) Bulkheads

In the embodiments of FIGS. 1 and 2, one bulkhead 39 is conveniently andpreferably mounted to the open end of section 30, and a second bulkhead39 to the section 32 at the opposite end of the embodiment 25 or 29,both end bulkheads 39 being mounted to the adjacent sections 30 and 32by means of, for example, a plurality of stainless steel nut and boltassemblies 42 (using the flanges 36), if desired, or like fasteningmeans.

Intervening between opposite ends of the trough defining section(s),other bulkheads can be utilized between trough defining sections. Forexample, the bulkhead 39 that is located between each of the respectiveadjacent tank sections 32 and 30 of stages 26/27 and 27/28 of embodiment25 is conveniently and preferably mounted to these respective tanksections 32 and 30 by means of, for example, a plurality of preferablystainless steel nut and bolt assemblies 42 (preferably using the flanges36) or the like. To provide a sealing engagement between each of thebulkheads 39 and adjacent portions of the sections 30 and 32 inembodiments 25 and 29, a conventional sealant means, such as a gasketstrip 43 (see FIG. 2), is continuously preferably extended initially asa ribbon or the like in conveniently initially applied in contact withthe flanges 36. Thus, in effect, each stage in an embodiment of aninventive RBC such as embodiment 25 is longitudinally begun and ended(defined) by a pair of longitudinally spaced, parallel bulkheads, suchas a bulkhead 39 pair or the like.

As shown in FIG. 2 for RBC embodiment 29, a terminal bulkhead can bemodified, if desired, to provide an apertured bulkhead, such as thebulkhead 39 a. Bulkhead 39 a is provided with an aperture 49 (shown inphantom), here preferably and illustratively rectangularly shaped.Aperture 49 can be provided with a valve, such as, for example, a simplegate valve 50 having a vertically slidable, rectangularly configuredgate valve plate 51 which can overfit the aperture 49 and which has eachof its opposite side edge portions engaged with a different verticallyextending track defined in each of a different one of a pair of spaced,parallel channel members 52 that are each affixed (by screws, adhesiveor the like, not detailed) to respective side portions of the bulkhead39 a. Thus, the opposite side edge portions of the valve plate 51 arevertically slidable along each of the respective channel members 52 sothat the aperture 49 can be closed or adjusted to some desired openingby the vertical position of the valve plate 51.

A bulkhead can be comprised of metal or plastic or a combinationthereof, as those skilled in the art will appreciate. An aperturedbulkhead can be variously structured, as desired. The relationshipbetween the sections 30, 31, and 32 and an associated pair of bulkheads39 is such that a hemicylindrical tank or trough region is definedbetween each of the longitudinally adjacent but spaced bulkheads 39.Profiles of various bulkheads 39 are illustrated in FIGS. 12-14B. FIG.12 shows for comparison purposes the profile of bulkhead 39. FIG. 13illustrates the profile of an exemplary intertrough or interstagebulkhead. FIG. 14 illustrates the profile of an alternative bulkhead 39b relative to bulkhead 39 a. The bulkhead 39 b illustratively has aplumbing fitting (not detailed) at an exit portal near or just above itsbottom center. Bulkhead 39 c of FIG. 14A illustrates a reinforcedintermediate bulkhead that can support a bearing block subassembly 84and associated shaft assembly 76, as described herein. Bulkhead 39 d ofFIG. 14B illustrates a reinforced end bulkhead that can support abearing block subassembly 84 and associated shaft assembly 76, asdescribed herein.

Preferably, a bulkhead, such as a bulkhead 39, 39 a, 39 b, 39 c or 39 d,has defined medially in its top edge region a laterally broad notch ordepression 44 that has a horizontally extending bottom surface. Thedepression 44 is useful for support purposes, as herein explained. Thedepression 44 can be variously utilized.

For example, each depression 44 is adapted to receive over edge adjacentsurface portions thereof a plurality of side brace supports 46 (see FIG.2) that are suitable for the support of a shelf structure 47. In RBCembodiments 25 and 29, a shelf structure 47 is placed on each bulkhead39. Each shelf structure 47 preferably has, as shown, a set of six suchbrace supports 46, the positioning of the brace supports 46 being suchthat there are three pairs of brace supports 46 located at each bulkhead39, the members of each pair being in opposed relationship relative toeach other on each side of each bulkhead 39 at depression 44. Each bracesupport 46 is illustratively triangularly configured and all bracesupports are conveniently similarly sized. Each brace support 46 has oneside leg that is adjacent to the bulkhead 39 and extends vertically, asecond side leg that extends horizontally but perpendicularly relativeto the one leg side, and a third or hypotenuse side extending diagonallybetween outer end portions of each leg side. Over upper surface portionsof each of the horizontally extending leg sides of each set of six bracesupports 46 is positioned a flat, preferably rectangularly sided shelfmember 47 that is secured to the set of brace supports 46 by adhesive,stainless screws or the like. The shelf member 47, the brace supports46, the bulkhead 39 and the depression 44 cooperate to provide supportof a bearing block subassembly 84, such as hereinbelow described.

For another example, in place of the set of brace supports 46 for eachshelf member 47, a cross sectionally square or rectangular tube member150 can be employed, such as, for instance, a length of a mid portion 77of a shaft assembly 76 or the like. The tube member 150 (see, forexample, FIGS. 14A, 14B, and 44) is located horizontally against atleast one side and preferably against opposite sides, of the bulkhead39. One side of the tube member 150 is bonded by adhesive or the like toadjacent portions of the bulkhead surface 39, and the adjacent side ofeach tube member 150 is preferably located so as to be flush with thebottom of each adjacent depression 44. When a shelf support member 47 isextended and positioned over the depression 44, it is thus supported bythe adjacent side surface portions of two tube members 150.

To counteract a possible tendency for an end bulkhead in an operatingRBC embodiment to bulge outwards in response to internal water pressure,particularly when the width of a bulkhead 39 is at least about 72″ orgreater (about 96″ being a particularly common or typical bulkheadwidth), the tube member 150 on the exterior side surface of an endbulkhead can be extended laterally so that the tube member 150 extendstransversely across the width of a bulkhead 39, thereby bracing andreenforcing the bulkhead 39 in its upper portions where the effect ofwater pressure is greatest.

As those skilled in the art will appreciate, many different alternativearrangements and configurations are possible to achieve a supportplatform at each bulkhead, as desired, for a bearing block subassembly84.

One presently preferred internal structure for a bulkhead 39 isillustrated in FIG. 15. Bulkhead 39 has a high performance polyvinylchloride core 109. Core 109 on each opposed face thereof is providedwith three layers 110, 111, and 112. The layers 110, 111, and 112 eachcomprise a high performance, bi-directional fiberglass mat on apolyester or a polyvinylester matrix. This bulkhead 39 is preferablyproduced by the vacuum infusion forming method. Those skilled in the artwill readily appreciate that various structures and constructiontechniques can be employed in the assembly of a bulkhead. Owing todifferences in fabrication procedures, sometimes closer dimensionaltolerances can be achieved using thermoformable plastic materials thanthermosettable plastic materials, as those skilled in the art willappreciate.

A bulkhead 147 that is suitable for use with the trough forming section30.1 of FIG. 20 and the trough forming section 30.1′ of FIG. 25 isillustrated in FIG. 24. This bulkhead 147 is regardable as beinggenerally trapezoidally configured and its downwardly and outwardlysloping opposite sides are adapted to mate with the correspondinglysloping sides of the supporting leg members 34.2 and 34.1 of the troughforming section 30.1.

A support bulkhead 148 is illustrated in FIG. 26 that is suitable foruse in supporting longitudinally adjacent trough sections relative to anunderlying ground or floor surface. The bulkhead 148 is located betweentwo adjacent trough forming sections, such as section 30.1′ of FIG. 25is shown in FIG. 26. The internal surface contour of this bulkhead 148preferably matches the internal contour of each of the longitudinallyadjacent pair of trough defining sections 30.1′ with the bulkhead 148connected therebetween and functioning to support the pair of sections30.1′. Thus, the length of a particular trough defining section need notfix the length of a stage.

(D) Contactor Drum Assemblies and Subcomponents

As shown in FIGS. 1, 2, 5 and 6, the contactor drum embodiment 53 isusually comprised of one circular end plate 54 and a plurality ofassociated, longitudinally (relative to the RBC embodiment) adjacent,preferably corrugated circular sheets 56 that comprises the contactormedium or core. Various construction materials can be employed. Onepresent preference is for each of the sheets 56 to be comprised ofpolyvinyl chloride and for each of the plates 54 to be comprised ofglass-filled polyester or polyvinylchloride.

Preferably, the number of sheets 56 in a contactor member 53 ranges fromabout 4 to about 40 although a contactor member 53 can contain a feweror greater number of sheets 56, if desired. Preferably, each sheet 56has a relatively rigid corrugated configuration. The sheets 56 areconveniently and preferably bonded together at points of contacttherebetween by conventional means, such as heat sealing, adhesive orthe like. Factors such as the number of sheets, the size of thecorrugations, the manner in which the corrugations are formed andarranged between adjacent sheets, and the like, affect the flow rate andvolume of water that can pass through the channels or passageways 57which transversely extend through a contactor drum 53, as those skilledin the art will readily appreciate. For convenience, the group ofcorrugated sheets 56 used in a given contactor member 53 can be regardedas a core or bundle 55 (see FIG. 31 or FIG. 43) although a given bundle55 can contain more than one group of sheets 56.

A contactor drum 53 has an axial and longitudinally extending (relativeto an incorporating RBC embodiment) cross-sectionally squareshaft-receiving aperture 72 defined centrally through the end plate(s)54 and the sheets 56 of a bundle 55.

In a contactor medium, such as a bundle 55, the corrugations in theindividual sheets 56 may extend generally straight and transversely inand across a contactor drum member 53, such as shown in FIG. 6, forexample. Preferably, in a given contactor drum member 53, the individualsheets 56 have similar corrugations. The relationship between individualadjacent sheets 56 in a bundle 55 can be such that the apexes andadjacent valleys of the individual corrugations defined in and acrossone sheet member 56 correspond to and are adjacent to those in theadjacent sheet member 56 (see FIG. 6). Commonly, in a contactor medium,in individual sheets 56, the corrugations of one sheet 56 may, ifdesired, extend at an angle, such as, for example, about 60°, relativeto the corrugations in an adjacent sheet 56, as illustrated, forexample, in FIG. 6A.

Depending upon factors such as convenience and availability, thoseskilled in the art will appreciate that a contactor drum 53 can have acore 55 that is itself comprised of separately fabricated bundles ofcorrugated sheets 56 which are commercially available, and, when this isaccomplished, preferably the bundles 55 comprise a resulting compositeof bundles which are arranged in a stacked manner preferably so that thecorrugations in individual sheets 56 tend to extend in a generallycommon direction. A resulting multi-component composite can be heldtogether by straps, flat brackets, or the like, as desired. Preferably,and conveniently, in a bundle of sheets, the corrugation ridges (orapexes) in one sheet 56 are bonded (by heat sealing, adhesive, or thelike) to adjacent contacting ridges of the adjacent sheet 56, thereby todefine a plurality of adjacent, parallel passageways or channels 57(see, for example, FIG. 6) that extend chord-like transversely acrossand through a contactor drum member 53 from one perimeter face or edgeportion to an opposite perimeter edge portion.

A group of separately fabricated bundles 55, each comprised ofcorrugated sheet members placed in a bundle composite of selecteddimensions, can be cut with a band saw or the like so that the resultingassembled core structure 55 has a desired peripheral configuration, forexample, a drum-like or (preferably) partially drum-like, or (morepreferably) hemi-circular configuration that is adapted for use as asubcomponent in a drum member 53. In accord with the invention, apresent preference is to form and cut a composite so as to provideinitially a hemi-cylindrical drum member portion that has both acircular perimeter portion that extends about 180° and also a flatsurface portion that extends diametrically between circular perimeteropposite ends and corresponds to the diameter in a desired drum member53 (see FIG. 43). Each diameter edge surface has defined therein at itsmid-region a preferably right-angled notch or cut shape whichcorresponds to about one half of a preferred shaft mid-portion 77 takendiagonally. To assemble a contactor member 53, the diameter of each oneof a pair of these so formed hemi-cylindrical members is then broughttogether with the other preferably about a shaft mid-portion 77, therebylocating the central core of a drum member 53 on and about a shaftassembly, such as shaft assembly 76, thereby to define a completecontactor drum member 53. Conveniently and preferably, halves of thedrum member 53 are assembled about a shaft mid-portion 77 of a shaftassembly 76 in an RBC embodiment that is being assembled. The assemblyis conveniently accomplished by two men who can work cooperatively in aconfined area with simple tools. Conveniently and preferably, a shaftassembly 76 is already assembled and located in an RBC embodiment thatis being assembled conveniently and preferably using components andsubcomponents such as are provided by the present invention.

Each of the opposed, spaced, parallel sides of a drum member 53 core canbe associated with an end plate that is generally designated as 54, asmay be desired, depending upon the particular RBC design configuration.The end plate 54 can be variously structured; it can be, for example, aunitary, flattened disk-like structure, as illustrated, for example, inFIGS. 1 and 2, or, for example, an end plate assembly 54.1 that iscomprised to two interconnected rigid half disk-like members 54.1A and54.1B (a present preference) that meet along a common diameter, asillustrated, for example, in FIG. 31 or FIG. 35. When two such half-disklike members are employed, preferably mid-way along the diameter of eachhalf-disk, a right angled notch is cut or otherwise defined therein,each notch preferably corresponding to about one half of a preferredshaft mid-portion 77 taken diagonally. The so formed end plate 54.1 canbe assembled with other components and subcomponents of an RBCembodiment that is being assembled conveniently and preferably usingcomponents and subcomponents such as are provided by the presentinvention.

The half-disk like members 54.1A and 54.1B can be variously comprisedand assembled. One can provide each mid-diameter notch with a mating,angular steel perimeter insert 135 (see, for example, FIGS. 31, 43, and45) that is sized to slidably engage with and over a region ofmid-portion 77 so that a pair of inserts 135 extends about a shaft midportion 77. Screw means or adhesive means (not detailed) can be providedoptionally to associate together adjacent end portions of each pair ofsteel perimeter inserts 135 and/or to associate a steel perimeter insert135 with adjacent portions of a disk-like member 54.1A and 54.1B.

As shown in FIG. 31, for example, a pair of flattened fastening plates146 can be extended over the diameter and adjoining adjacent regions ofa combined pair of half-disk like members 54.1A and 54.1B. Each oppositeside portion of each plate 146 can be connected to or associated withthe associated such half-disk member 54.1 or the like by screws or thelike (not detailed). The inner end portions of each plate 146 can benotched to fit adjacently relative to the center notch or square shaftaperture of the assembled plate 54.1. After being brought together witha bundle 55 therebetween, the half-disk like members 54.1A and 54.1B canbe mounted by screws or the like to end regions of the retainer bracket102, as indicated in FIG. 43, that extends over the bundle 55, therebyto associate the spaced, parallel end plates 54.1 with core portions ofa drum member 53. A plate support is preferably located on each oppositeside of a contactor drum 53 when the drum 53 is used separately from,for example, a paddle wheel 60, about a shaft mid portion 77 (see FIG.31).

If desired, to aid in associating the half-disk like members 54.1A and54.1B, the diametrically extending edge portions of a pair of thehalf-disk like members 54.1A and 54.1B can be modified to achieve adowel butt joint arrangement such as illustrated in FIG. 33.Alternatively, such edge portions can be provided with a tongue andgroove arrangement such as illustrated in FIG. 34. Alternatively, suchedge portions can be provided with a bolted lap joint arrangement suchas illustrated in FIGS. 35 and 36.

In a fully assembled contactor drum member 53 that includes at least oneend plate 54 or 54.1, during rotation of the contactor drum member 53 ona rotating shaft assembly 76, wastewater which is present in a stage ofthe assembled and operating RBC can flow progressively into andtransversely through the drum member 53 (relative to the longitudinaldirection of an RBC trough), with the wastewater flowing through thechord-like passageways 57 defined by the corrugated sheets 56 from onecircumferential side portion of the contactor drum member 53 to another,as those skilled in the art will readily appreciate.

Although various techniques can be used, the manner or technique bywhich a set or group of corrugated sheets comprising a core 55 isassociated with an end plate 54 is believed to influence the durabilityof the resulting contactor 53 relative to a shaft assembly 76 with whicha contactor drum 53 is associated.

In assembling a contactor 53 comprised of two component halves around aportion of the cross-sectionally square mid-region 77 of a shaftassembly 76, it is presently preferred to employ a plurality ofelongated flat retainer bracket 102, of the type shown in FIG. 28, forexample, that each extends over and across a circumferential edgeportion of a contactor drum 53. Each bracket 102 has opposite endflanges 104 that are each fastened by screws or nut and bolt assembliesto a different side plate 54 or the like.

A plurality of retainer brackets 102, four, or more preferably six, percontactor drum member 53, are located at circumferentially equallyspaced inset intervals about each contactor drum member 53 and eachbracket 102 extends across a member 53 longitudinally (relative to anRBC embodiment). Each of the retainer brackets 102 has an elongatedflattened body 103 with a terminal perpendicularly extending flange 104defined at each opposite end thereof (relative to the body 103 of theretainer bar 102).

In a preferred assembly technique, a bracket 102 is turned 90° from itsspatial orientation shown in FIGS. 1 and 2 so that it has theorientation illustrated in, for example, FIGS. 29, 30, 32, 31, 43, and44.

Preferably, at least some of the brackets 102 used in a contactor drummember 53 are positioned so as to be generally radially aligned with aflat surface portion of the associated shaft mid-region 77. A bracket102 can be positioned so as to have a flat side surface adjacent to adrum member 53 circumference, as illustrated, for example, in FIGS. 1and 2, or, more preferably, can be positioned so as to have an edgeregion thereof generally radially oriented and extended into the drummember 53 as illustrated in FIGS. 30, 32, 43, and 44, for example. Toaccommodate each retainer bracket 102 in a drum member 53, preferably(as shown) portions of the corrugated sheet members 56 at the member 53circumference adjacent to each retainer bracket 102 are cut away (orotherwise removed) so that each bracket 102 is recessed in thecircumferential surface of the member 53 and the exteriorcircumferential surface portions of the resulting contact member 53remain uniformly generally circular.

In an RBC embodiment such as 25 or 29, for example, where a paddle wheel60 is adjacent to a drum contactor member 53, the relationship betweeneach of the retainer brackets 102, a plate such as 54, a contactor 53core, and each side plate 61 and 62 of the paddle wheel 60, ispreferably such that one flange 104 of a retainer bracket 102 can beconnected to plate 54 (preferably against an inside surface thereof)while the other flange 104 of the same bracket 102 can be connected toone plate 61 (preferably against an outside surface thereof) of a paddlewheel 61 with the body 103 extended over a circumferential portion ofthe contactor drum member 53 (see FIG. 43, for example). Preferredfastening means comprise nut and bolt assemblies (not shown) or thelike. Thus, as further detailed below, the need or desirability for twoside plates 54 can be avoided.

(E) Paddle Wheel Assemblies and Subcomponents

As shown in, for example, FIGS. 1, 2, 7, and 8, a paddle wheel assembly60 includes a pair of longitudinally (relative to an RBC embodiment)spaced, parallel, circular, coaxial side plates 61 and 62 comprised of athermoset resin, such as glass fiber filled polyester, for example, or athermoplastic resin, such as thermoformable polyvinylchloride, forexample. Other plastics and metals can be utilized, if desired.Preferably a paddle wheel has a cross sectionally square, axiallyextending aperture 73 defined through the center thereof.

Extending longitudinally between the side plates 61 and 62 are aplurality of generally radially oriented, elongated, circumferentiallypreferably equally spaced paddle blade members 64 that may be comprisedof glass fiber filled polyester, metal, or the like as may be desired.The number of paddle blade members 64 in a paddle wheel assembly 60 canvary, but a present preference is for the number of paddle blade members64 in a given paddle wheel assembly 60 ranges from about 8 to about 36with 15 being presently most preferred; however, a fewer or a greaternumber of paddle blades 64 can be employed, if desired. Here, each ofthe respective opposite sides of each of the paddle blades 64 extend inspaced, parallel relationship relative to each other in the paddle wheelassembly 60. Each side is provided with a flange 67 that isperpendicularly oriented relative to adjacent blade portions. Eachflange 67 is adapted to rest against portions of the adjacent plate 61or 62 and in effect close the side portions of each blade 64 relative tothe side plates 61 and 62.

As shown, for example, in FIGS. 7 and 8, in paddle wheel 60, each paddleblade member 64 has a generally longitudinally (relative to an RBCembodiment) flattened, radially elongated, straight extending mid-region66 that longitudinally extends perpendicularly between the side plates61 and 62. The inner terminal end region of each paddle blade member 64defines an angularly and radially projecting tongue flange 68. Theouter, terminal end region 69 ends adjacent to the perimeter of eachplate 61 and 62 and adjacent thereto each paddle blade member 64 iscurved and defines a cup-like region 71 that longitudinally extendsbetween adjacent portions of the plates 61 and 62.

To connect a flange 67 with adjacent portions of the side plates 61 and62, nut and bolt assemblies (not detailed) or the like can be used. Thetongue flange 68 of each paddle blade member 64 is mounted to the tongueflange 68 of an adjacent paddle wheel member 64 by means of a nut andbolt assembly 74 or the like. Thus, as assembled, the tongue flanges 68combine to define a type of hub 63 that is radially outwardly spacedrelative to the shaft aperture 73 in each side plate 61 and 62. Sealingmeans, not shown, may be used between adjacent component portions toavoid water passage during use of the paddle wheel assembly 60.

In a paddle wheel assembly 60, all of the terminally curved cup-likeportions 71 of each blade 64 have a similar curvature (see, for example,FIG. 8) and the direction and orientation of the curvature of each blademember 64 is similar. The effect of the curvature is to increase thefluid volume capacity of an individual blade 64 when, during rotation ofthe paddle wheel assembly 60, a blade 64 reaches or exits the surface ofan aqueous medium in an RBC state. Characteristically, a blade 64displaces a portion of an aqueous medium as it enters the medium whenoperating in a stage of an RBC or the like and lifts a portion of theaqueous medium (due to a localized vacuum effect) as it exits from theaqueous medium. With a paddle wheel assembly 60, both displacement andlifting of water occur during paddle wheel 60 rotation. Using an oddnumber of blades 64 in a paddle wheel 60, such as 15, reduces the effectof water impact and provides for a smoother operating process.

When an axially and rotatably mounted paddle wheel 60 has a fluidic(which can be a liquid like water or a compressed gas such as air) forceapplied particularly to surface portions of the paddle blade members 64,the paddle wheel 60 reacts and rotates responsively, as those skilled inthe art will readily appreciate. Various equipment configurations can beemployed to apply a fluidic force to the blades 64 of a paddle wheel 60.

For example, as illustrated in FIG. 39, a stream of preferablypressurized water exiting from the mouth or nozzle of pipe 151 thatterminates over the level of aqueous medium in an operating RBC stage isprovided whereby the water so released from the pipe is directed toimpact against the paddle wheel blade members 64 of a paddle wheel 60,thereby to cause the paddle wheel 60 to rotate or continue to rotate.The water thus provided can be from any convenient source including thewastewater itself that is being processed in an RBC embodiment.

For another example, as illustrated in FIG. 40, a pressurized stream ofwater (relative to the aqueous medium present in a stage) is releasedfrom the mouth or nozzle of a pipe 152 that terminates under the aqueousmedium level in an operating RBC stage and is directed so as to impactagainst the paddle wheel blade members 64 of a paddle wheel 60, therebyto cause the paddle wheel 60 to rotate or continue to rotate. The waterthus provided can be from any convenient source including the wastewateritself that is being processed in an RBC embodiment.

For another example, as illustrated in FIG. 40A, a stream of acompressed gas, conveniently air, is conveyed through a manifold 153 andreleased through a ball valve 154 or the like into a delivery pipe 155that, following circumferentially the internal contour of the adjacenttrough 156, releases the air adjacent the bottom of the trough 156 so asto impact against the paddle wheel blade members 64 of a paddle wheel60, thereby to cause the paddle wheel 60 to rotate or continue torotate.

The amount and/or pressure of fluid so released against paddle bladescan be regulated either manually or automatically. Preferably, inaddition to the applied fluidic pressure, a paddle wheel 60 and theapplied fluid are so arranged that the paddle blades 64 are induced torotate by the weight of the fluid accumulating between circumferentiallyadjacent paddle blades 64. Typically, the amount and/or pressureachieved is sufficient to produce a desired rotation rate of the shaftassembly 76 with which the paddle wheel 76 is associated. Variousoperating options are available. As indicated herein, the shaft assembly76 in a given stage of an RBC embodiment, for example, can be, asdesired, (a) independently powered (rotatably driven) by the associatedpaddle wheel 60, (b) independently powered by the paddle wheel 60 incombination with an electric motor, (c) independently powered by anelectric motor (not detailed) with the paddle wheel 60 undriven (notpowered), (d) powered by the associated paddle wheel 60 in combinationwith other coaxially associated shaft assemblies 76 that areinterconnected together in an RBC embodiment and that are themselvespowered, or otherwise as may be desired.

A paddle wheel assembly can be variously constructed and assembled. Analternative embodiment 107 of a paddle wheel subassembly is illustrated,for example, in FIG. 9. Components of paddle wheel embodiment 107 thatare similar to those of paddle wheel embodiment 60 are similarlynumbered but with the addition of prime marks added thereto forconvenient identification purposes. In the paddle wheel 107, the paddlewheel blade members 64′ each extend radially and in a straightconfiguration. A flange 108 at the inner end of each blade member 64′ ismounted by nut and bolt assemblies to a separate preformed hub member106 that is located in radially outwardly spaced relationship toaperture 73′ in side plate 62′. FIG. 10 illustrates the centralstructure of the paddle wheel assembly 107.

FIG. 37 illustrates an embodiment of a paddle wheel assembly 114 whichis similar to paddle wheel assembly 107 except that the paddle wheel 114has 15 paddle blade members 64′ each with a outer terminal curvaturesimilar to that in blades 64.

FIG. 38 illustrates fragmentarily an embodiment of a paddle wheelassembly wherein each paddle wheel blade member 64′ at its inner end isprovided with a flange 108′ that is adapted to engage a slot 138 definedin a preformed hub member 139.

FIGS. 41 and 42 illustrate fragmentarily an embodiment of a paddle wheelassembly which can be comprised of thermoformed polyvinyl chloridesheeting, if desired. Each side plate 61′ and 62′ (the latter notdetailed) is defined by halves which each have a flange 143 definedalong their respective diameters except for a shaft receiving notchdefined medially. These halves abuttingly engage the halves about asquare shaft, such as mid-portion 77, and are mounted together byscrews, nuts and bolts, rivets or the like (not detailed). Theindividual paddle blade members 64′ can have a configuration similar tothe blade members 64 and can similarly be mounted to the side plates 61′and 62′. To provide a desired spacing between circumferentially adjacentblade members 64′, enhance blade structure, and aid in mounting, apositioning and rigidifying bracket 141 is inserted between adjacentmembers 64′ with a receiving pocket being provided in each bladestructure 64′ that is adapted to receive what can be regarded as theleading edge of a bracket 141. Each bracket 141 is provided with a pairof opposed side flanges 142 that extend at about 90 degrees relative tothe flat body of the bracket 141. The flanges 141 have holes definedtherein to enable mounting to an adjacent side plate 61′ or the like.The bracket 141 also limits water passage between adjacent blade members64′.

(F) Shaft Assemblies, Bearing Assemblies and Support Assemblies

Various shaft, bearing, and bearing support arrangements can be used inassembling an RBC embodiment using components and subcomponents providedby this invention, as those skilled in the art will readily appreciate.Presently preferred is a shaft assembly 76 (see FIG. 2, for example)which includes medially a cross-sectionally square and preferably hollowmid-portion 77 plus a cross-sectionally round and preferably solidcylindrical portion 78, 79 at each end opposite end region thereof.

A single shaft assembly 76 can be connected to longitudinally adjacent,coaxial other shaft assemblies that are each comprised of a mid portion77 plus a cylindrical opposite end portions 78 and 79 to achieve aplurality of coaxial shaft assemblies 76 that in one preferred formrotate together. A present preference is to have each opposite endportion 78 and 79 comprised of steel and to have each mid portion 77comprised of steel or more preferably pultruded glass fiber filledpolyester although other constructions can be employed.

For portion 77 connection with portions 78 and 79, into the open end ofeach opposite end of the mid-portion 77 a plug 81 is preferably insertedand held in place by means of an adhesive, welding, or the like. Therearward (inward) end of each shaft end portion 78, 79 is preferablyfixedly connected by welding or the like with an enlarged transverselyextending mounting plate 82 that preferably has a square perimeter. Therelationship between the cross-sectional diameter of each respective endof the shaft end portions 78,79 and the perimeter dimensions of themounting plate 82 are such that, with the rearward end of each of theshaft end portions 78, 79 mounted to a different one of the mountingplates 82, the axis of each shaft end portion 78, 79 is coaxiallyalignable with the axis of the mid-portion 77. The rearward end of eachshaft end portion 78, 79 is preferably located adjacent each oppositeend of the mid-portion 77 with a plate 82 therebetween. A plurality(preferably four, as shown) mounting screws 83 or the like convenientlypass through each of the plates 82 and threadably engage adjacentportions of each plug 81, thereby mounting each shaft end portion 78, 79to a different opposite end of the mid-portion 77. As so assembled, aresulting shaft assembly 76 has a length that extends longitudinally andaxially (relative to the trough sections employed) between, for example,a longitudinally adjacent pair of the bulkheads 39 at each opposite endof a stage 26, 27, or 28 of RBC embodiment 25 or of the stage of the RBCembodiment 29.

To support each shaft end portion 78, 79 and an associated bearing blockassembly 84 (described below) or the like, a shelf structure 47 (abovedescribed) is associated with each bulkhead 39. Each shelf structure 47is associated with and supports a different bearing block subassembly84, and each shaft end portion 78, 79 of each shaft section 76 isassociated with a different bearing block subassembly 84. When the endportions 78, 79 of two different shaft sections 76 are each soassociated with a bearing block assembly 84, the axis of shaft endportions 78 and 79 are adapted to be substantially coaxial with the axisof the hemi cylindrical tank or trough chamber defined, for example, bythe associated combination of the interior side walls 33 of thelongitudinally aligned tank sections 30, 31, 32 defining the stages 26,27, and 28 of embodiment 25, or defined by the associated combination ofthe interior side walls 33 of the longitudinally aligned sections 30, 32of the single stage of embodiment 29.

For association with a bearing assembly 84 or the like, each shaft endportion 78 and 79 preferably has a remote outer end region 87 (see FIG.4) defined therein that is provided with a reduced diameter relative tothe diameter of the main adjacent body of each shaft end portion 78, 79,and each such remote outer end region 87 is provided with alongitudinally extending key-way slot. In a bearing assembly 84, overeach remote outer end region 87, a split collar 86 is mounted. Thus, onecollar half 86 b is adapted to mount over one half of the remote outerend region 87 of each shaft end portion 78 and 79 and has definedtherein a longitudinally extending key slot. The respective key slots ineach of the collar half 86 b and end region 87 are adapted tocooperatively receive a key 88 (one key 88 for each shaft end portion78, 79), thereby preventing collar half 86 b from being rotatablerelative to each end region 87. The other collar half 86 a is adapted tomount over the remaining half of the remote outer end region 87 of eachshaft end portion 78 and 79. Screws 89 extend off-diameter through thecollar halves 86 a and 86 b to engage them together about each endregion 87, thereby engaging the respective shaft end portions 78 and 79.

Screws 99 extend longitudinally but off-diameter through the collarhalves 86 a and 86 b to engage them together with the shaft end portions78,79 adjacent, connected and extending coaxially. When an RBCembodiment incorporates a paddle wheel, or particularly when an RBCembodiment incorporates a plurality of longitudinally adjacent stages,and one stage is to have its shaft assembly 76 operate independentlyfrom an adjacent stage, the bearing block subassembly 84 can be employedbetween such a longitudinally adjacent pair of shaft assemblies 76.These shaft assemblies 76 can be independently operated relative to eachother by simply removing the screws 99.

When, for example, a pair of longitudinally adjacent shaft assemblies 76are to be coaxially interconnected together through a bearing blocksubassembly 84, the end portion 78 of one shaft section 76, and the endportion 79 of a second shaft section 76, each with an associated splitcollar 86, are associated with a bearing block assembly 84, and in thebearing block assembly 84 the axis of each shaft assembly 76 ispositioned coaxially relatively to the other. Preferably a similarbearing block subassembly 84 is associated with each shelf member 47 inan RBC embodiment. Those skilled in the art, will readily appreciatethat, if desired, alternative other bearing block assemblies andsupports can be utilized, if desired.

Referring to FIGS. 3 and 4, the bearing block subassembly 84 includes abase block 93 and an associatively engageable cap block 94. Each block93 and 94 has defined centrally therein a hemicylindricalcollar-receiving cavity 96 in a mid-region thereof. The cavity 96 ateach of its opposed opposite ends interconnects with a hemi-cylindricalshaft-accommodating cavity 97 (paired). The configuration of blocks 93and 94 and of the cavities 96 and 97 are such that, when the cap block94 is associated over the base block 93, the cavities 96 and 97 arematingly arranged so that each of the two combined hemi-cylindricalshaft accommodating cavities 97/97 and the combined hemi cylindricalcollar receiving cavities 96/96 are coaxial with one another with theshaft accommodating cavities 97/97 being located in longitudinallyspaced relationship relative to each other, one cavity 97/97 being ateach end of the collar-receiving cavity 96/96.

As positioned in a bearing block subassembly 84, a spacer pad 98 (seeFIG. 4) is preferably located between adjacent split collars 86. Collarconnecting screws 99 (preferably two, each preferably about 180 degreesapart from the other) are longitudinally extended through and connectedwith the adjacent split collars, thereby interconnecting the shaftsection 76 of end portion 78 with the shaft section 76 of end portion 79in the bearing block subassembly 84. Preferably, each screw 99 extendsin an opposite direction relative to the other. The cap block 94 isassociated with the base block 93 and also with the shelf member 47 by aplurality (preferably four) of nut and bolt assemblies 101. Thus, as sojoined by means of a bearing block assembly 84, two or more shaftassemblies 76 can be coaxially connected together to comprise amulti-component shaft subassembly for use in fabricating or operating anRBC embodiment.

Sometimes there is a need to adjust the length of the mid-portion 77 ofan embodiment of the shaft assembly 76. A starting mid-portion 77 iseasily shortened by cutting a long mid-portion 77 to achieve a desiredlength. One manner of easily lengthening a starting mid-portion 77 is toadd or extend one end thereof a desired length with an extendingmid-section 77A. Such a lengthening is conveniently achieved asillustrated in FIG. 16. Thus, into an open end of a too shortmid-section 77 is slidably extended one end of a cross-sectionallysquare, elongated connector block 123 (comprised of metal or plastic)whose body dimensions are selected to permit the block 123 to fitslidably into that end. A raised shoulder band 124 (comprised of metalor plastic) of narrow width is associated with and extends around theexterior mid-region of the block 123. The band 124 provides a stop thatlimits the extent to which the block 123 can extend into a length of amid section 77. The opposite end of the block 123 is extended into theopen end of another mid-portion 77A whose length when added to that ofmid-portion 77 equals a desired length for a mid-portion comprised ofmid-portion 77 plus mid-portion 77A after adjacent respective ends ofsection 77 and 77A are each fully engaged with block 123. The block 123can be bonded by adhesive (not shown) to the associated section 77 or77A, and/or the block 123 can be secured to a section 77 or 77A by meansof a headless nut and bolt assembly (not shown) which extends preferablyperpendicularly through aligned holes transversely extending through ablock 123 and a mid-portion 77 or 77A, the alignable hole in each beingarranged to be in spaced, adjacent relationship to a nearly end thereof.

Another manner in which a mid-portion 77 can be lengthened by anextension portion 77A is illustrated in FIG. 18. Here, two lengths thatwhen added together equal a desired length for a total mid portion 77are held in adjacent coaxial relationship by an overfitting clamp 130comprised to two terminally flanged C-type halves 130A and 130B that areengageable with one another by nut and bolt assemblies 131.

A contactor drum assembly or a paddle wheel assembly such as provided bythe invention can each be associated at a desired longitudinal locationalong a mid-portion 77 on a shaft assembly 76 by various means. Onesuitable means is illustrated in FIG. 19 where a mid-portion 77 isprovided with ridges 132 (conveniently comprised of metal or plastic)that extend circumferentially around the square mid-portion 77, theridges 132 being bonded to the mid-portion 77. The location of theridges 132 is such that, after a contactor drum assembly or paddle wheelassembly is assembled around the mid-portion 77, the ridges 132 areengaged therewith and serve to retain selected edge portions of acontactor drum or a paddle wheel assembly end walls at their respectivedesired centers.

Alternatively, the end plates 82 of a suitably arranged shaft assembly76 can be placed adjacent to a contactor drum or paddle wheel assemblyin an RBC embodiment thereby to hold a contactor drum, a paddle wheelassembly, or a combination of contactor drum(s) and paddle wheelassembly in association with the mid portion 77.

Various motor interconnection and power transfer arrangements can beemployed in an RBC embodiment. One manner in which a shaft assembly 76may be connected to a motor drive is illustrated in FIGS. 11 and 17. Aspur shaft 117 is coaxially extended from an end portion 78 that isrotatably supported by bearing block assembly 84 as above explained. Thespur shaft 117 is keyed to a relatively large driven sprocket 118 thatis generally coplanar with a relatively small drive sprocket 120 that isassociated therewith by a chain drive 119. The drive sprocket 120 isfixed to the drive shaft of a conventional geared motor drive assembly121 located exteriorly but adjacent to an RBC embodiment.

(G) Combinations of Shaft Assemblies with Contactor Drum and PaddleWheel Assemblies

An important feature of the present invention is that embodiments of theinventive contactor drums and paddle wheel assemblies can be combined toachieve various novel and improved combinations over and about shaftassemblies.

In the illustrative but presently preferred combination shown in FIG. 1,in a single stage, such as stage 26, a paddle wheel assembly 60 islocated between two contactor drum assemblies 53. Each contactor drumassembly 53 is oriented spatially so that an outermost corrugated sheetmember 56 is adjacent to a different one of the side plates 61 and 62 ofthe paddle wheel assembly 60. Thus, only one side plate 54 located onthe outer side of each contactor drum assembly 53 is needed. Each of theretainer brackets 102 extends at the circumference over and against thecore of each drum assembly 53 with the each bracket 102 opposite endmounted to a different end plate 54 and 61 and also plate 54 and 62.Each bracket 102 also serves to associate each contactor drum 53 withthe paddle wheel assembly 60. Preferably and as shown, each shaftassembly 76 has a mid-portion 77 that is about equal to the combinedthickness of the paddle wheel assembly 60 and the two contactor drumassemblies 53. Thus, each of the mounting plates 82 is adjacent adifferent one of the side plates 54 of the contractor drum assemblies 53and serves to retain the drum assemblies 53 and the paddle wheelassembly 60 associated with the mid-portion 77.

FIG. 43 illustrates another embodiment of a type similar to that shownin FIG. 1 where the contactor drums 53 and the paddle wheel 60 aresimilarly assembled together as in FIG. 1 from subcomponents for eachusing a shaft assembly as shown FIG. 19. FIG. 1 and FIG. 2 do notindicate subcomponent possibilities for the contactor drums 53 or thepaddle wheel 60 for reasons of simplicity. In FIG. 43, the contactorhalves are identified as 53A and 53B, illustrative brackets 102 areradially oriented, and the paddle wheel halves are identified as 60A and60B. To enhance structural integrity, each outside plate 54 o of eachcontactor drum 53A/53B can, if desired, be optionally provided with asecond two component plate 54 p, and each such second plate 54B has itshalves and associated respective diameters turned 90° relative to thecorresponding respective positions in plate 54 o. The shaft assembly 76is provided with both mounting plates 82 and ridges 132 for use inpositioning the contactor drums 53A/53B and the paddle wheel 60A/60B onthe mid portion 77.

FIG. 44 illustrates an embodiment of the type similar to that shown inFIG. 2 where the contactor drum 53 and the paddle wheel 60 are assembledfrom subcomponents for each using a shaft assembly as shown in FIG. 16and trough sections are assembled from components as shown in FIG. 25.An additional but optional two-piece side plate 62′ is provided toreinforce the side plate 62 of the two piece paddle wheel 60, the sideplate 62′ being rotated 90° relative to the side plate 62. Here, eachtwo piece plate 54, 61, 62 and 62′ is being assembled with a connectingplate 146. A stabilizing side plate 62′ that is adjacent to plate 62 isturned 90° relative to the side plate 62 to provide better structuralintegrity for the paddle wheel 60.

FIG. 45 illustrates an RBC stage embodiment incorporating a singlecontactor member 53, this embodiment being assembled from the contactordrum components of FIG. 31, a shaft assembly of the type shown in FIGS.19 and 43, a trough defining structure of the type shown in FIG. 27, andbulkheads of the type shown in FIG. 24, for example.

FIGS. 43-45 illustrate assemblies of various component combinations thatcan be employed an RBC embodiment of the invention using the inventivesubcomponents and components. Other assemblies will be apparent to thoseskilled in the art.

As those skilled in the art will readily appreciate, use situations mayoccur where a single stage can be utilized which comprises a single tanksection 30 that is associated with a bulkhead 39 at each opposite endthereof. That stage can be provided with a shaft section or assembly 76which has a mid-region 77 and end regions 78 and 79 that are adapted forusage in such stage, and each bulkhead 39 is provided with a shelfmember 47 and set of supports 46 and with a bearing support assembly 84.That stage can be associated with a single contactor member 53, a singlepaddle wheel assembly 60, or otherwise as may be desired.

As those skilled in the art will also readily appreciate, a single stagecan be comprised of a plurality of longitudinally interconnectedsections 30 with a bulkhead 39 associated at each opposite end thereof.Although the mid-portion 77 of a shaft section 76 can be substantiallylengthened so as to adapt a shaft section 76 for usage in a stage havingsuch a plurality of interconnected sections 30, it is presentlypreferred that a stage not incorporate more than about 4 suchinterconnected sections 30 and that a single group of interconnectedshaft assemblies 76 be not longer that about eight feet.

In the practice of the present invention, preferably at least twosimilar tank housing sections (each unitarily formed or comprised ofmulticomponents such as described herein) are directly or indirectly(perhaps through a bulkhead) interconnected together. Each tank sectionhas both inside wall portions that define a generally hemi cylindricaltrough region that extends longitudinally therethrough, and outside wallportions that define section support means extending downwardly fromupper opposite side regions of said inside wall portions for abuttingengagement with a support surface. The tank housing sections each havegenerally similar inside and outside dimensions, respective end wallportions that are abuttingly engageable with one another. The tankhousing sections are so oriented relative to one another that, when theend wall portions are so abuttingly engaged, a hemi cylindrical troughregion is defined by the so engaged sections and such trough defines acommon longitudinal axis relative to the hemicylindrical trough region.Mounting and sealing means is provided for engaging adjacent pairs ofthe tank housing sections together in a generally fluid tightengagement.

For operation, an RBC embodiment, such as embodiment 25 or embodiment29, can be associated with conventional auxiliary equipment, as thoseskilled in the art will readily appreciate. For example, as illustratedin FIG. 11, wastewater (not detailed) can be preliminarily charged to apretreating device, such as a settling tank 115 or the like, if desired,for preliminary removal of particulate solids by settling, filtering, orthe like. From settling tank 115, wastewater is transported through aconduit 116 to the first stage 26 of an RBC 25, or the like, as desired.Into stage 26 the wastewater is discharged from conduit 116 against thepaddlewheel assembly 60, inducing it to rotate and thereby revolve theshaft assembly 76. Additionally, a stub shaft 117 is connected to theend bearing block subassembly 84 and a power input sprocket 118 isconnected with the projecting portion of shaft 117. Sprocket 118 isassociated with a drive chain 119, and the drive chain 119 in turn isengaged with the drive sprocket 120 of a motor reducer drive assembly121 (conventional). Thus, when the motor drive assembly 121 iselectrically powered, the shaft assembly 76 and its mid-portion 77 arerotated and the drive assembly 121 augments the power produced byrotation of the paddle wheel assembly 60.

As is apparent from the foregoing specification and the appendeddrawings, the invention is susceptible to being embodied in variousalternative and modified embodiments which may differ from theparticular teachings here disclosed. It should be understood that I wishto embody within the scope of the present patent all such alternativeand modified embodiments as reasonably and properly come with the scopeof this contribution to the art.

1-28. (canceled)
 29. A unitarily formed trough defining section for arotating biological contactor, said section having a longitudinallyextending trough defined therethrough.
 30. A housing section for arotating biological contactor, said housing section comprising— (a) atrough defining portion having a longitudinally extending trough definedtherethrough and a lateral side defined on each side of said trough, (b)a side wall portion on each said lateral side for supporting said troughdefining portion with said trough in a gravitationally lower positioncompared to upper side portions of said trough defining portion, (c)each of said trough defining portion and said side wall portions beingunitarily formed.
 31. The housing section of claim 30 wherein at leastone of said side wall portions is separate from but engageable with onesaid lateral side.
 32. The trough defining section of claim 29 which isunitarily formed in combination with one side wall portion on onelateral side thereof, and which is detachably engageable with anotherside wall portion on the opposite lateral side thereof, said side wallportions in combination with said trough defining section being adaptedto support said trough defining section in a working position.
 33. Thetrough defining section of claim 29 which is in combination withdetachably engageable side wall support members on each lateral sidethereof. 34-47. (canceled)